A smart City Application: a fully Controlled Street Lighting Isle Based on Raspberry-Pi Card, a ZigBee Sensor Network and Wimax

2. State of the Art 
In this area, the efforts are focused on the use of alternative energies for the power supply of new 
lighting technologies [5–7], which allow obtaining considerable energy savings. Within lighting 
technologies, Light Emitting Diodes (LEDs) assure the possibility of switching on the lamp without the 
preheating typical of halogen ones; a very high lighting efficiency; low power consumption; a superior 
life time and quick switching times not comparable to those of older technologies (only incandescent 
lights have a lower lighting time, but with very big power consumption and the shortest time life); less 
sensitivity to transient phenomena, which have a big impact on other technologies, allowing thousands 
of lightings without the risk of lamp failure. These innovative characteristics allow development of a 
new remote-control system based on intelligent lamp posts that also send information to a central control 
system in order to simplify management and maintenance issues [1–4] also using holistic and bottom-up 
design strategies [1]. Within these researches, a relevant topic is the use of new sensor networks (wireless 
and not) and communication technologies, both to locally manage the lamp posts, but also sensor 
networks, and to send data towards a remote center [1–5,8–17]. 
Based on the best technologies and on the SG paradigm, our proposal describes a solution for an 
extremely diffused hostile scenarios, often neglected by the municipalities, but which have an enormous 

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Sensors 
2014
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social relevance, and where both the mains and the internet signal provided by the most diffused 
communication technologies (ADSL and 3G) are not available. 
3. The Layers Architecture 
The architecture of the system has been conceived as a hierarchical layers structure for the full control 
of “unities” made up of sensors, actuators and local control cards. Each layer performs some control 
activities and transmits information to the other layers. The architecture foresees three layers called 
apparata, local control and remote control. 
In the “apparata layer” we consider all the hardware and software designed for the autonomous and 
automatic control of the single apparatus or unit. This layer communicates with the higher one and 
vice 
versa
using a ZigBee mesh wireless tlc network particularly suitable for closed devices and low bit
rates [3]. The local control unit collects the data received from the single units to check their activity and 
functionality. It is realized with a RaspBerry-Pi control card, which collects and locally elaborates data 
from the single apparatus verifying that there are no problems. If a problem(s) occurs, the card sends an 
error message on the internet exploiting the upper layer. The latter is realized with a WiMAX
trans-receiver, which is connected, 
via
radio link, to the World Wide Web. Figure 1 shows the 
architecture of the system.